Electric-lamp socket.



G. B. THOMAS. ELECTRIC LAMP SOCKET. APPLICATION FILED FEB.23, 1912.

1,072,271 Patented Sept. 2, .1913.

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UNITED STATES PATENT OFFICE.

GEORGE B. THOMAS, 0F BRIDGEPORT, CONNECTICUT, ASSIGNOR TO THE BRYANT ELECTRIC COMPANY, OF BRIDGEPORT, CONNECTICUT, A CORPORATION OF CON- NECTICUT.

ELECTRIC-LAMP SOCKET.

Specification of Letters Patent.

Patented Sept. 2,1913.

To all whom it may concern Be it known that I, Gronon B. THOMAS, a citizen of the United States of America, and residing at Bridgeport, in the county of Fairficld and State of Connecticut, have invented a certain new and useful Improvement in Electric-Lamp Sockets, of which the following is a specification.

My invention relates to electric lamp sockcts and particularly to the switch mechanism thereof, the object of my invention being 'to increase the safety, efficiency and current-carrying capacity of the switch mechanism by providing a device which smothers the are which tends to form between the parting edges of the switch contacts on the opening of the switch.

In the accompanying drawings, Figure 1 is a side elevation of the body of a stand ard electric lamp socket in which my invention is embodied in one form; Fig. 2 is a similar view showing the switch mechanism in another position; Fig. 3 is a perspective of the rotary switch contact; Fig. 4 is a plan of the same with my improved insulating device thereon; Fig. 5 is a cross section of the latter on the line 5--5, Fig. 4; and Fig. 6 is an inverted perspective of the same. Fig. 7 is a dropped perspective showing the operating ratchet and rotary switch piece detached with the ratchet plate tilted up to show the ratchet teeth.

The socket illustrated is, in its main fcatures, of the type illustrated in the Hubbell Patent No. 693,799, and comprises insulating buttons A and B spaced apart by standards 10, 11 and 12, and between which the switch mechanism is mounted on a central spindle 13. This mechanism comprises an actuating pawl plate 14 pivoted on the spindle 13 and subjected to the action of a return spring 15, in well known manner. The plate 14 carries as usual a chain rail 16 to which is secured the pull chain 17. The downwardly angled lugs 18 of the plate 14 engage the edges of the radial arms 19, on the rotary switch contact 20, mounted upon the spindle 13 beneath said plate. The stationary switch contact 22 is mounted on one of the inclines ot' the ratchet-formed boss 21, which projects from the upper face of the button B, while the arms 23 of the rotary switch piece ride over the inclines of the boss 21 as usual.

When one of the arms 23 leaves the top of the incline upon which the stationary contact 22 is mounted, on the break of the switch circuit, there is a tendency to form an are between the parting edges of the stationary contact 22, and of the rotary switch contact 23. This tendency, in the case of an excessive current passing through the lamp circuit, is quite marked, and introduces an element of danger which is ordinarily provided against by automatic cutouts of limited current carrying capacity installed in the circuit. These necessarily limit the number of lamps which may be mounted in a single circuit. To eliminate this danger, I now propose to mount upon the rotary contact member an insulator which, upon the opening of the switch, is automatically interposed between the parting edges of the rotary and stationary switch contacts, and forms a barrier between the same, so that not only is any are which tends to form smothered thereby, but the accidental formation of an are between the contacts while the switch is in the off position is prevented.

In the particularembodiment of my invention illustrated, which must be regarded as merely exemplary, since there are various ways of accomplishing the same end, I

mount upon the upper face of the rotary contact a ring 24 of insulatin material which is provided with downwardly projecting shoulders 25, following the incline of the arms 23. Upon the opening of the switch, these shoulders are automatically interposed in the space between the lower end of the contact arm 23 and the upper end of the stationary contact 22, thus completely blocking the space between these contacts, as shown in Fig. 2. To further separate these contacts from each other, I provide the insulating ring with a downwardly projecting peripheral skirt 26 which prevents the formation of an are around the interposed shoulder 25 between the outer edges of the contacts. The insulating ring 24 with its skirt 25 thus forms a rotary insulating barrier and casing which, in combination with the base B and the hub of the boss 21, completely incloses each of the contact arms 23 in the off or open position of the switch-complctely insulating the same from the stationary contact 22. In order that this insulating ring may lie flush with the upper face of t e contact plate so as not to interfere' with the operation of the actuating plate 14, the contact arms 23 are ofi'set downwardly at a point beyond .those portions of the radialarms 19 which form the cooperatingratchets for the-downwardly angled 'pawls of the plate 14, and in this offset the m'sulatin ring is fitted asshown in Fig. 5.

Upon t e' actuation of the switch, the rotaryswitch member and insulating ring rise on the inclines of the boss 21, and one of the rotary contact arms 23 passes over the stationary contact 22. As. the lower end of therntary contact arm 23 escapes the upper end of the stationary contact 22 the spr ng 15 forces the rotary contact and Insulating y ring down upon. the. succeeding incline of the-boss 21. The shoulder 25 and the skirt 26 of thexinsulating ring during this downward travel of the contact '23 are interposed between the parting edges of the contacts and not only snuif out any arc that might tend to'fo'rm between the parting edges of the contacts, but serve to incase the rotary contact arm and positively insulate it from .the stationary contact.

It is obvious that) this device so increases the capacity of the switch that a much heavances, comprising a series of inclined iercurrent maybe broken thereby with safety, and consequently the number of lamps on a given circuit may be materially increased.-

I claim as my invention 1. A switch mechanism for electric a pliances, comprising a series of inclined aces and a stationary contactthereon, in combination with a rotary switch-contact having contact arms to pass over said inclined faces and contact, means to intermittently rotate the movable contact, in combination with insulating material interposed between the parting edges of said stationary and rotary contactsupon the o ening of the switch, to-

gether with a perip eral 'askirt of insulating. material depending aroundiithe outer nor-- mally exposed edge of said contact arms. v 2. A swltch mechanism for" electric appliaces A and a stationary contact-thereon, in combination with a rotary switch contact having Witnesses:

contact arms to pass over said inclined faces and contact, means to intermittently rptate the movable contact, in combination wlth. a

ring of insulating material overlying'said contact arms and provided with downw'ardfy'.5

inclined shoulders following-the incline" said contact arms, whereby said shoulders are interposed between the parting edgesoi said stationary and rota contacts upon the opening of the switch, sald contact a 'mS bfiing offset at their upper end'to permit the insulating ring to lie flush with the upper face of the rotary contact. i

3. A switch mechan1sm' p tionary insulating base, a stationary sw tch contact thereon, a rotary contact cooperating with the'stationary contact and a'rotary .mip i'ising sta insulating body cooperating with the stationary insulating base to completely inclose and insulate the rotary contmt from' the stationary contactin the oif position of the switch.

4. In an electric switch, a rotary switch member comprising a central bearing plate having outwardly extending arms an 7 arouate downwardly angled contact wings ofi'set at their junction with said outwardly ex tending arms.

5. In an electric switch, a 'rotary switch;

member comprising a central bearing plate, outwardly extending arms forming a ratchet element and arcuate downwardly angled extensions oflset from said'arms to form con-' name to this specification, in the presence of two subscribing witnesses.

GEORGE 'B', THOMAS.

H.- M. WIoHnRT, 1H. BADEAU.

topics of this patent may be obtained for five cents each, by addressing the "Commissioner of Patents,

Washington, 30; 0. 

